A highly infectious bacterium that causes shigellosis, spread mainly by infected food handlers and poor hand hygiene.
A highly infectious bacterium that causes shigellosis, spread mainly by infected food handlers and poor hand hygiene. Shigella is a bacterium that causes shigellosis, an illness marked by diarrhoea that is often bloody, along with stomach cramps, fever and a feeling of needing to pass stool urgently. It spreads through the faecal-oral route, and because it takes only a very small number of bacteria to cause infection, it passes easily from person to person and through food handled by someone who is infected. Contaminated water and raw foods such as salads and other ready-to-eat items are also linked to outbreaks. Symptoms usually appear one to three days after exposure and last around five to seven days. The main food-safety concern is an infected food handler who prepares food, particularly ready-to-eat items, with inadequate hand hygiene after using the toilet. People can carry and spread Shigella for a period after they feel better, and it can also spread within households, childcare centres and other close settings, which is why hygiene and exclusion of unwell staff are so important. The most important control in an Australian food business is excluding sick food handlers and enforcing thorough handwashing. Anyone with diarrhoea must not handle food and should stay away from food handling until well clear of symptoms, following state health department advice, because Shigella can still be shed after recovery. Handwashing with soap and running water after using the toilet and before handling food is critical given how few bacteria are needed to infect someone. Ready-to-eat foods that are handled directly, such as salads, sandwiches and garnishes, carry the greatest risk, so bare-hand contact should be minimised and good hygiene enforced. Clean, potable water for washing produce, well-maintained toilet and handwashing facilities, and clear policies requiring staff to report gastro symptoms and stay home all help break the chain of transmission. A worker recovering from a gastro illness returns to prepare salads while still shedding Shigella, and handwashing at the venue is poor. Because only a tiny dose is needed to infect someone, the ready-to-eat salads become a source of infection, and several customers develop bloody diarrhoea and cramps over the following days. Excluding the worker until fully clear of symptoms and enforcing thorough handwashing would have prevented the spread.
Frequently asked questions
How does Shigella spread through food?
Mainly through infected food handlers with poor hand hygiene contaminating ready-to-eat food, as well as through contaminated water and raw foods. Only a very small number of bacteria is needed to cause infection, so it spreads easily.
What are the symptoms of shigellosis?
It causes diarrhoea that is often bloody, stomach cramps, fever and an urgent need to pass stool. Symptoms usually start one to three days after exposure and last about five to seven days.
When can an infected food handler return to work?
They must not handle food while unwell and should follow state health advice on exclusion, since Shigella can be shed after symptoms stop. Thorough handwashing after using the toilet is essential when they do return.
Which foods are most often involved?
Ready-to-eat foods handled directly, such as salads, sandwiches and garnishes, are common vehicles because they are not cooked after handling. Contaminated water and raw produce can also carry the bacteria.
How can businesses prevent it?
Exclude staff with gastro symptoms, enforce thorough handwashing, minimise bare-hand contact with ready-to-eat food, use clean water to wash produce, and keep toilet and handwashing facilities in good order.
